You forgot to use the mutex in your process function. Normally there'd be more options like using atomics - but Haxe sadly still doesn't provide any of those. I'd be interested in having a look at those clicks, could you provide a small sample application for me to listen to them?

You need to put the exe in the windows folder, not the windows-build folder. But that's all, there's zero dependencies. See if your friend can at least run a very simple project like the Shader sample (for that one the exe itself is sufficient because it doesn't even load a file).

Kha does come with an up to date version of Haxe. But Kode Studio doesn't come with an up to date version of Kha currently because I didn't update Kode Studio in two years. Get a recent version of Kha from GitHub and set the Kha Path option in Kode Studio.